Lane Johnson situation explains Doug Pederson's left tackle plan

Eagles will miss Johnson on line if suspended (1:11)

Louis Riddick breaks down what it would mean for the Eagles if they lose Lane Johnson to a 10-game suspension. (1:11)

PHILADELPHIA -- As Doug Pederson explained his plans for the Philadelphia Eagles' preseason opener Thursday night, an obvious question arose.

With Pro Bowl left tackle Jason Peters unavailable due to a quadriceps injury, Pederson said he planned to start Matt Tobin in his place. Tobin, who made the team as an undrafted rookie in 2013, has started 20 games in three years with the Eagles. All of those starts were at guard.

Why not Lane Johnson? The right tackle has started 44 regular-season games since the Eagles drafted him with the No. 4 pick in the 2013 NFL draft. All along, the Eagles said that Johnson could eventually move to the left side. That factored into their decision to sign him to a new five-year contract last winter with $35 million in guaranteed money.

And yet Tobin was lining up at left tackle in practice this week, and will do so against the Tampa Bay Buccaneers Thursday night.

"Well, we just want to make sure Lane is comfortable at the right spot," Pederson said Monday. "The other thing, with the tackles we have, Tobin has done a nice job filling in over there. Just giving him that opportunity there, as well. I think Tobin's having a great camp. So we haven't felt the need, offensively, to move Lane over there at this time."

When news broke Tuesday that Johnson could be facing a 10-game suspension for violating the NFL policy on performance-enhancing drugs, Pederson's decision made sense. If the Eagles have been aware of Johnson's impending suspension, they would not be preparing Johnson to step in if Peters gets injured.

Tobin, Dennis Kelly and Andrew Gardner are veterans who could play tackle. Fifth-round pick Halapoulivaati Vaitai is another candidate. But Pederson may be planning for going into the season without Johnson for the first 10 games.

Johnson has reportedly appealed the suspension. So it makes sense for the Eagles to let him continue practicing with the rest of the starting offensive line. If Johnson's appeal is successful, he will need the preseason work alongside right guard Brandon Brooks.

If Johnson is suspended, Pederson and the Eagles will have two problems. Tobin, Kelly, Gardner or Vaitai would have to replace Johnson at right tackle. But the Eagles will have to have a replacement ready for Peters, as well. The 34-year-old Peters missed two games and parts of several others last season due to nerve damage that caused pain in his quadriceps.

Johnson was suspended four games for a PED violation in 2014. He said at the time that he took a prescription medication without realizing it was on the NFL's list of banned substances. Johnson did not check with the Eagles' medical staff before taking the medication.

The Eagles knew about the 2014 suspension when they negotiated Johnson's new contract, which includes a $10 million signing bonus. Because of the previous suspension, Johnson's contract includes language that eliminates the guarantee on $25 million included in the contract.

Johnson could still receive that money, but the Eagles would be able to release him at any point without paying the now non-guaranteed money.

It appears the Eagles have been dealing with the possibility of a suspension for some time. Pederson said Monday that he couldn't expand on his plans for replacing Peters, if necessary.

"I can't get into the 'what ifs' at this time," Pederson said.

On Tuesday, we discovered that one of those "what ifs" was the possible suspension of Johnson.